[PATCH v4 01/59] do_faccessat(): import pathname only once

Al Viro
2026-01-08T07:36:48Z

Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.

Since we have the default logics for use of LOOKUP_EMPTY (passed iff
AT_EMPTY_PATH is present in flags), just use getname_uflags() and
don't bother with setting LOOKUP_EMPTY in lookup_flags - getname_uflags()
will pass the right thing to getname_flags() and filename_lookup()
doesn't care about LOOKUP_EMPTY at all.

The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/open.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/open.c b/fs/open.c
index f328622061c5..f3bacc583ef0 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -468,6 +468,7 @@ static int do_faccessat(int dfd, const char __user *filename, int mode, int flag
int res;
unsigned int lookup_flags = LOOKUP_FOLLOW;
const struct cred *old_cred = NULL;
+ struct filename *name;

if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
return -EINVAL;
@@ -477,8 +478,6 @@ static int do_faccessat(int dfd, const char __user *filename, int mode, int flag

if (flags & AT_SYMLINK_NOFOLLOW)
lookup_flags &= ~LOOKUP_FOLLOW;
- if (flags & AT_EMPTY_PATH)
- lookup_flags |= LOOKUP_EMPTY;

if (access_need_override_creds(flags)) {
old_cred = access_override_creds();
@@ -486,8 +485,9 @@ static int do_faccessat(int dfd, const char __user *filename, int mode, int flag
return -ENOMEM;
}

+ name = getname_uflags(filename, flags);
retry:
- res = user_path_at(dfd, filename, lookup_flags, &path);
+ res = filename_lookup(dfd, name, lookup_flags, &path, NULL);
if (res)
goto out;

@@ -527,6 +527,7 @@ static int do_faccessat(int dfd, const char __user *filename, int mode, int flag
goto retry;
}
out:
+ putname(name);
if (old_cred)
put_cred(revert_creds(old_cred));

--
2.47.3